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Revision 1.8 by root, Sun Jul 31 17:24:05 2005 UTC vs.
Revision 1.9 by root, Tue Aug 16 23:33:38 2005 UTC

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62 argument when the given syscall has been executed asynchronously. 62 argument when the given syscall has been executed asynchronously.
63 63
64 All functions expecting a filehandle keep a copy of the filehandle 64 All functions expecting a filehandle keep a copy of the filehandle
65 internally until the request has finished. 65 internally until the request has finished.
66 66
67 The filenames you pass to these routines *must* be absolute. The reason 67 The pathnames you pass to these routines *must* be absolute and encoded
68 for this is that at the time the request is being executed, the current 68 in byte form. The reason for the former is that at the time the request
69 working directory could have changed. Alternatively, you can make sure 69 is being executed, the current working directory could have changed.
70 that you never change the current working directory. 70 Alternatively, you can make sure that you never change the current
71 working directory.
72
73 To encode pathnames to byte form, either make sure you either: a) always
74 pass in filenames you got from outside (command line, readdir etc.), b)
75 are ASCII or ISO 8859-1, c) use the Encode module and encode your
76 pathnames to the locale (or other) encoding in effect in the user
77 environment, d) use Glib::filename_from_unicode on unicode filenames or
78 e) use something else.
71 79
72 aio_open $pathname, $flags, $mode, $callback 80 aio_open $pathname, $flags, $mode, $callback
73 Asynchronously open or create a file and call the callback with a 81 Asynchronously open or create a file and call the callback with a
74 newly created filehandle for the file. 82 newly created filehandle for the file.
75 83
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119 $_[0] > 0 or die "read error: $!"; 127 $_[0] > 0 or die "read error: $!";
120 print "read $_[0] bytes: <$buffer>\n"; 128 print "read $_[0] bytes: <$buffer>\n";
121 }; 129 };
122 130
123 aio_readahead $fh,$offset,$length, $callback 131 aio_readahead $fh,$offset,$length, $callback
124 Asynchronously reads the specified byte range into the page cache,
125 using the "readahead" syscall. If that syscall doesn't exist (likely
126 if your OS isn't Linux) the status will be -1 and $! is set to
127 "ENOSYS".
128
129 "aio_readahead" populates the page cache with data from a file so 132 "aio_readahead" populates the page cache with data from a file so
130 that subsequent reads from that file will not block on disk I/O. The 133 that subsequent reads from that file will not block on disk I/O. The
131 $offset argument specifies the starting point from which data is to 134 $offset argument specifies the starting point from which data is to
132 be read and $length specifies the number of bytes to be read. I/O is 135 be read and $length specifies the number of bytes to be read. I/O is
133 performed in whole pages, so that offset is effectively rounded down 136 performed in whole pages, so that offset is effectively rounded down
134 to a page boundary and bytes are read up to the next page boundary 137 to a page boundary and bytes are read up to the next page boundary
135 greater than or equal to (off-set+length). "aio_readahead" does not 138 greater than or equal to (off-set+length). "aio_readahead" does not
136 read beyond the end of the file. The current file offset of the file 139 read beyond the end of the file. The current file offset of the file
137 is left unchanged. 140 is left unchanged.
138 141
142 If that syscall doesn't exist (likely if your OS isn't Linux) it
143 will be emulated by simply reading the data, which would have a
144 similar effect.
145
139 aio_stat $fh_or_path, $callback 146 aio_stat $fh_or_path, $callback
140 aio_lstat $fh, $callback 147 aio_lstat $fh, $callback
141 Works like perl's "stat" or "lstat" in void context. The callback 148 Works like perl's "stat" or "lstat" in void context. The callback
142 will be called after the stat and the results will be available 149 will be called after the stat and the results will be available
143 using "stat _" or "-s _" etc... 150 using "stat _" or "-s _" etc...
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159 166
160 aio_unlink $pathname, $callback 167 aio_unlink $pathname, $callback
161 Asynchronously unlink (delete) a file and call the callback with the 168 Asynchronously unlink (delete) a file and call the callback with the
162 result code. 169 result code.
163 170
171 aio_rmdir $pathname, $callback
172 Asynchronously rmdir (delete) a directory and call the callback with
173 the result code.
174
164 aio_fsync $fh, $callback 175 aio_fsync $fh, $callback
165 Asynchronously call fsync on the given filehandle and call the 176 Asynchronously call fsync on the given filehandle and call the
166 callback with the fsync result code. 177 callback with the fsync result code.
167 178
168 aio_fdatasync $fh, $callback 179 aio_fdatasync $fh, $callback
169 Asynchronously call fdatasync on the given filehandle and call the 180 Asynchronously call fdatasync on the given filehandle and call the
170 callback with the fdatasync result code. Might set $! to "ENOSYS" if 181 callback with the fdatasync result code.
171 "fdatasync" is not available. 182
183 If this call isn't available because your OS lacks it or it couldn't
184 be detected, it will be emulated by calling "fsync" instead.
172 185
173 SUPPORT FUNCTIONS 186 SUPPORT FUNCTIONS
174 $fileno = IO::AIO::poll_fileno 187 $fileno = IO::AIO::poll_fileno
175 Return the *request result pipe file descriptor*. This filehandle 188 Return the *request result pipe file descriptor*. This filehandle
176 must be polled for reading by some mechanism outside this module 189 must be polled for reading by some mechanism outside this module
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257 If you queue up many requests in a loop it it often improves speed 270 If you queue up many requests in a loop it it often improves speed
258 if you set this to a relatively low number, such as 100. 271 if you set this to a relatively low number, such as 100.
259 272
260 Under normal circumstances you don't need to call this function. 273 Under normal circumstances you don't need to call this function.
261 274
275 FORK BEHAVIOUR
276 IO::AIO handles all outstanding AIO requests before the fork, destroys
277 all AIO threads, and recreates them in both the parent and the child
278 after the fork.
279
262SEE ALSO 280SEE ALSO
263 Coro, Linux::AIO. 281 Coro, Linux::AIO.
264 282
265AUTHOR 283AUTHOR
266 Marc Lehmann <schmorp@schmorp.de> 284 Marc Lehmann <schmorp@schmorp.de>

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